A wide variety of downhole tools may be used within a well bore in connection with producing hydrocarbons from a hydrocarbon formation. Downhole tools such as frac plugs, bridge plugs, and packers, for example, may be used to seal a component against casing along the well bore wall or to isolate one pressure zone of the formation from another. In addition, perforating guns may be used to create perforations through casing and into the formation to produce hydrocarbons.
Downhole tools are typically conveyed into the well bore on a wireline, tubing, pipe, or another type of cable. In conventional systems, the operator estimates the location of the downhole tool based on this mechanical connection and also communicates with the tool through this mechanical connection. For example, the operator may send communications to the downhole tool via the cable to command the setting of a plug in the well bore, or to command the firing of a perforating gun. This mechanical connection may be subject to various problems including time consuming and costly operations, increased safety concerns, more personnel on site, and risk for breakage of the connection.
Therefore, a need exists for downhole tools that may be lowered, pumped, or released into the well bore, and that are operable to self-determine their location within the well bore without receiving location communications from the surface. Further, a need exists for downhole tools that are operable to self-activate without receiving command communications from the surface.